Camera device and monitor system

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a monitor system including a monitor camera device and an image recording/reproducing device and in particular, to a technique for detecting failure of the monitor camera device.

2. Description of the Related Art

JP-A-9-74553 (Patent Document 1) is an example of the related art of the field of the invention. This invention has an object “to automatically detect imaging disturbance and take a countermeasure” and a solution as follows. “A system includes: a first monitor device <b>1</b> having a CPU <b>1</b>, a ROM <b>2</b>, a RAM <b>3</b>, an operation processor <b>4</b>, a frame memory <b>5</b>, and a communication control unit <b>7</b> for imaging a monitor object by a monitor camera <b>6</b>, compressing a still image of the monitor object, and transmitting it as image data; and a second monitor device <b>2</b> having a CPU <b>11</b>, a ROM <b>12</b>, a RAM <b>13</b>, an operation processor <b>14</b>, a frame memory <b>15</b>, a display device <b>16</b>, a communication control unit <b>17</b>, and an alarm device <b>18</b> for receiving the image data from the first monitor device <b>1</b> inputted via a communication line <b>8</b>, decompressing the image data to restore the still image of the monitor object, and displaying it to be monitored. If it is detected that a data amount of the image data obtained by compressing the image captured by the monitor camera <b>6</b> in the first monitor device <b>1</b> is smaller than a predetermined data amount, a message telling that something is wrong in imaging by the monitor camera <b>6</b> is displayed with alarm in the second monitor device.”

SUMMARY OF THE INVENTION

Recently, as the number of crimes increases, an attention is paid on a monitor system formed by a plurality of monitor camera devices connected to an image recording/reproducing device for recording a region to be monitored. A recorded image is important because it is used for identifying a criminal. However, an image from the camera devices used in such a monitor system may fails by a mischief such as spraying a liquid or failure inside the camera devices. In this case, no image of the monitor region is recorded and it becomes impossible to check the condition of the monitor image afterwards.

In the camera device used for monitoring, a lens unit failure may be caused by failure of an exposure mechanism (iris) for controlling exposure or a shutter speed failure may be caused by failure of a CCD (Charge Coupled Device) sensor. When the exposure mechanism or the CCD sensor has failed, incident light amount becomes excessive and an image of so-called ““Wash Out”” appears, i.e., the entire image becomes white. When an image of “Wash Out” has appeared, it is necessary to detect and notify that an abnormal condition has occurred.

However, the conventional technique of the aforementioned Patent Document 1 can only recognize a uniform dark flat image such as sprayed liquid and no consideration is taken for detecting an image of “Wash Out” Furthermore, when an image is flat, an abnormal condition is detected even if the image is in a normal state. That is, the detection accuracy is low. These problems reduce the reliability of the camera device.

It is therefore an object of the present invention to provide a camera device and a monitor system capable of improving reliability.

In order to achieve the aforementioned object, the camera device according to the present invention includes: an iris unit for varying the incident light amount; a shutter control unit for varying the shutter speed of an imaging element; a signal processing unit for processing an image signal from the imaging element; an exposure target calculation unit for calculating a control value for controlling the iris unit or the shutter control unit based on information on the signal level from the signal processing unit so that the exposure light amount will be a target value; and an abnormal state judgment unit for judging whether the state is abnormal according to the control value by the exposure target calculation unit and the information on the signal level from the signal processing unit.

Moreover, in order to achieve the aforementioned object, the monitor system according to the present invention includes: a camera device for detecting a malfunction of the iris unit for varying the incident light amount or the shutter control unit for varying the shutter speed of the imaging element and reporting the malfunction information; and a monitor device for receiving the malfunction information from the camera device. Furthermore, the monitor device has a malfunction information detection unit for detecting malfunction information, a malfunction position judgment unit for specifying a malfunction position from the malfunction information, and a malfunction report unit for reporting the malfunction. When malfunction is detected by the malfunction information detection unit, the malfunction report unit reports it outside.

According to the present invention, it is possible to improve reliability of the camera device and the monitor system.

Other objects, characteristics, and merits of the present invention will be clear from the description of embodiments of the present invention with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

<figref idref="DRAWINGS">FIG. 1</figref> is a block diagram of a monitor camera device according to the present invention.

<figref idref="DRAWINGS">FIG. 2</figref> is a block diagram of a monitor system according to the present invention.

<figref idref="DRAWINGS">FIG. 3</figref> is a flowchart of a malfunction detection process performed by the monitor camera device according to the present invention.

<figref idref="DRAWINGS">FIG. 4</figref> is a flowchart of a malfunction report process of the monitor device according to the present invention.

<figref idref="DRAWINGS">FIGS. 5A and 5B</figref> are brief diagrams showing screen examples and image signals.

<figref idref="DRAWINGS">FIGS. 6A</figref>, <b>6</b>B, and <b>6</b>C show display examples when an alarm has occurred.

<figref idref="DRAWINGS">FIG. 7</figref> is a flowchart of a malfunction detection process of the monitor camera device according to a second embodiment of the present invention.

<figref idref="DRAWINGS">FIG. 8</figref> is a flowchart of a malfunction report process of the monitor device according to the second embodiment of the present invention.

<figref idref="DRAWINGS">FIG. 9</figref> is a block diagram of the monitor camera device according to a third embodiment of the present invention.

DESCRIPTION OF THE EMBODIMENTS

Description will now be directed to an embodiment of the monitor system according to the present invention with reference to <figref idref="DRAWINGS">FIGS. 1 to 8</figref>. It should be noted that in this embodiment, the image signal complies with the NTSC scheme and the burst signal in color signals has frequency normally set to 3.58 MHz.

1. Embodiment 1

Explanation will be given on a monitor system according to a first embodiment of the present invention with reference to <figref idref="DRAWINGS">FIGS. 1 to 6</figref>.

Firstly, explanation will be given on the configuration and the outline of the operation of the monitor camera device according to the present invention with reference to <figref idref="DRAWINGS">FIG. 1</figref>. <figref idref="DRAWINGS">FIG. 1</figref> is a block diagram of the monitor camera device according to the present invention.

<b>1</b> denotes the monitor camera device; <b>11</b> denotes a lens iris as a iris mechanism formed by a lens <b>111</b> and an iris open/close unit <b>112</b> for opening and closing the iris so as to vary the exposure; <b>12</b> denotes a an imaging element such as a CCD sensor; <b>13</b> denotes a CDS/AGC for sampling an image signal from the CCD sensor <b>12</b> and performing automatic gain control; <b>14</b> denotes an A/D converter for converting an analog image signal into a digital image signal; <b>15</b> denotes a signal DSP (Digital Signal Processor) for performing various signal processes such as separation of the image signal into a luminance signal and a color signal; <b>16</b> denotes a Y/CMIX for mixing the signals separated into the luminance signal and the color signal by the signal processing DSP <b>15</b>; <b>17</b> denotes a microcomputer as a control unit for controlling the entire monitor camera device <b>1</b> and detecting malfunction information; <b>18</b> denotes a CCD shutter control circuit as a shutter control unit for varying/controlling the shutter speed of the CCD sensor <b>12</b>; and <b>19</b> denotes an iris drive circuit for varying/controlling the lens iris unit <b>11</b>. Moreover, the monitor camera device <b>1</b> according to the present embodiment includes a buzzer <b>201</b> and an LED (Light Emitting Diode) <b>202</b> for reporting a malfunction by the monitor camera device itself upon detection of the malfunction by the microcomputer <b>17</b> and an audio circuit <b>203</b> for reporting by audio from a speaker <b>204</b> and an Ethernet transmission circuit <b>205</b> for transmitting the malfunction information to an external reception device <b>32</b> such as a PC and a mobile telephone via the Ethernet and a general line. Furthermore, the signal processing DSP <b>15</b> includes a signal level detection unit <b>151</b> for detecting the signal level of the image signal, a camera signal processing unit <b>152</b> for performing various signal processes such as separation into a luminance signal and a color signal, and a color encode unit <b>153</b> for switching the burst signal in the color signals by the malfunction information detected by the microcomputer <b>17</b> and reporting it as malfunction information. Moreover, the microcomputer <b>17</b> consists of: an exposure target calculation unit <b>171</b> for calculating a control value for controlling the lens iris unit <b>11</b>, the iris drive circuit <b>19</b>, and the CCD shutter control circuit <b>18</b> so that the exposure will be set to a target value based on the information on the signal level from the signal level detection unit <b>151</b>; a malfunction judgment unit <b>172</b> to judge whether the monitor camera device is in an abnormal state according to the control value obtained by the exposure target value calculation unit <b>171</b> and information on the signal level from the signal level detection unit <b>151</b>; a malfunction position detection unit <b>173</b> for specifying the malfunction position; and a malfunction report unit <b>174</b> for reporting the malfunction information and the malfunction position information.

Here, explanation will be given on the outline of the malfunction detection operation according to the present invention.

Firstly, in a normal state, an image signal of an object captured via the lens iris unit <b>11</b> to the CCD sensor <b>12</b> is inputted as a digital image signal via the CDS/AGTC <b>13</b> and the A/D <b>14</b> to the signal level detection unit <b>151</b>. According to the signal level information from the signal level detection unit <b>151</b>, the exposure target calculation unit <b>171</b> calculates such an iris control value or a shutter speed control that the image signal level will be at a predetermined level and controls the open/close degree of the iris open/close unit <b>112</b> by the iris drive unit <b>19</b> or the shutter speed of the CCD sensor <b>12</b> by the shutter control circuit <b>18</b>, so as to obtain a target exposure. On the other hand, the image signal introduced via the signal level detection unit <b>151</b> is separated into the luminance signal and the color signal by the camera signal processing unit <b>152</b> and is performed with various signal processes. The color encode unit <b>153</b> adds a burst signal depending on the malfunction information to the color signal variously processed in the camera signal processing unit <b>152</b>. The color signal is then mixed with the luminance signal by the Y/CMIX <b>16</b> to become an image signal, which is transmitted to the monitor device.

Next, explanation will be given on a case when the lens iris unit <b>11</b> or the iris drive circuit <b>19</b> has failed to cause an abnormal state. When the lens iris unit <b>11</b> or the iris drive circuit <b>19</b> has failed and the iris open/close unit <b>112</b> cannot be closed to cause an entirely bright image and a large signal level, the exposure target calculation unit <b>171</b> sends an iris control value for closing the iris open/close unit <b>112</b> to the iris drive circuit <b>19</b>. However, when the iris open/close unit <b>112</b> or the iris drive circuit <b>19</b> has failed, the iris open/close unit <b>112</b> cannot be closed and “Wash Out” is caused in the image. Here, because of the image of “Wash Out”, the signal level from the signal level detection unit <b>151</b> is higher than the predetermined value and the iris control value is to close the iris open/close unit <b>112</b>. It is judged that this state is out of the normal control range and the malfunction judgment unit <b>172</b> judges that a malfunction has occurred and the malfunction position detection unit <b>173</b> specifies that the lens iris unit <b>11</b> or the iris drive circuit <b>19</b> has failed. Furthermore, since the output of the iris drive circuit <b>19</b> is detected, if the output of the iris drive circuit <b>19</b> (drive voltage of the lens iris unit <b>11</b>) is not the target value for the iris control value, it is possible to judge that the iris drive circuit <b>19</b> has failed and if the iris drive circuit <b>19</b> has not failed, it is possible to judge that the lens iris unit <b>11</b> has failed. According to the information on the malfunction position specified by the malfunction position detection unit <b>173</b>, the malfunction report unit <b>174</b> controls the color encoder unit <b>153</b> as follows. If the iris drive circuit <b>19</b> has failed, the frequency of the burst signal in the color signal is switched from 3.58 MHz of the NTSC scheme to 4.43 MHz of the PAL scheme. If the lens iris unit <b>11</b> has failed, the burst signal is turned OFF and malfunction information is sent to the monitor device side. The monitor device side detects the burst signal in the color signal and performs an alarm display in accordance with the failure position together with the identifier of the monitor camera which has failed to report the failure to an administrator.

Simultaneously with switching of the burst signal in the color signal, the malfunction report unit <b>174</b> reports the malfunction by changing the volume or level of the buzzer <b>201</b> and ON/OFF repetition, by changing the brightness, the color, and the flashing cycle of the LED <b>202</b>, and by performing audio guide about the malfunction occurrence and the malfunction position from the speaker <b>204</b> according to the failure position information. Thus, the monitor camera device itself reports the malfunction and a person in the vicinity of the camera can also know the malfunction and can rapidly take a countermeasure. Furthermore, the malfunction information and the malfunction position information are transmitted to a destination of the external reception device <b>32</b> such as a preset PC and a mobile telephone via the Ethernet transmission circuit <b>205</b>. The administrator can know the malfunction at a remote place via the PC or the mobile telephone and can rapidly take a countermeasure.

Explanation will be given on a case when the CCD sensor <b>12</b> has failed to cause an abnormal state. When the CCD sensor <b>12</b> has failed, the shutter speed cannot increase and the entire image becomes bright and the signal level becomes large. For this, the exposure target calculation unit <b>171</b> sends a shutter control value to increase the shutter speed to the shutter control circuit <b>18</b>. However, since the CCD sensor <b>12</b> has failed, the shutter speed does not reach the maximum speed and “Wash Out” occurs in the image. Here, because of the image of “Wash Out”, the signal level from the signal level detection unit <b>151</b> is higher than the predetermined threshold value and the shutter control value indicates a maximum speed. Since it is judged that this state is out of the normal control range, the malfunction judgment unit <b>172</b> judges that a failure has occurred and the malfunction position detection unit <b>173</b> judges that the CCD sensor <b>12</b> has failed. The malfunction report unit <b>174</b> controls the color encoder unit <b>153</b> to periodically turn ON/OFF the burst signal in the color signal, thereby sending malfunction information to the monitor device side. The monitor device side detects that the burst signal in the color signal periodically turns ON/OFF and performs an alarm display on the screen together with the identifier of the monitor camera which has failed to notify the administrator. It should be noted that failure of the CCD shutter control circuit <b>18</b> includes the failure of the CCD sensor <b>12</b>.

Simultaneously with the periodic ON/OFF of the burst signal in the color signal, the malfunction report unit <b>174</b> reports the malfunction occurrence and the malfunction position by using the buzzer <b>201</b>, the LED <b>202</b>, and the speaker <b>204</b> according to the malfunction position information. Furthermore, the failure information and the malfunction position information are transmitted to a preset destination such as a PC and a mobile telephone via the Ethernet transmission circuit <b>205</b>. The administrator can rapidly know the malfunction at a remote place via the PC or the mobile telephone and rapidly take a countermeasure.

Next, explanation will be given on the configuration and operation of the monitor system according to the present invention with reference to <figref idref="DRAWINGS">FIG. 2</figref>. <figref idref="DRAWINGS">FIG. 2</figref> is a block diagram of the monitor system according to the present invention.

<b>2</b> denotes a monitor device for recording an image signal from the monitor camera device <b>1</b> and reporting malfunction information to an administrator; <b>21</b> denotes a burst detection unit which is a malfunction information detection unit for detecting a burst signal in the color signal; <b>22</b> denotes a control unit including a malfunction information judgment unit <b>221</b> for specifying a malfunction position according to the burst signal information detected by the burst detection unit <b>21</b> and a malfunction report unit <b>222</b> for controlling the buzzer <b>231</b> and the OSD display content according to the malfunction information; <b>231</b> denotes a buzzer for reporting the malfunction by audio; <b>232</b> denotes an LED for reporting the malfunction by light emission; <b>234</b> denotes a speaker driven by an audio circuit <b>233</b> to report the malfunction by audio; <b>235</b> denotes an Ethernet transmission circuit for transmitting the malfunction information via the Ethernet or the general line to the external reception device <b>32</b> such as a PC and a mobile telephone; <b>24</b> denotes a signal processing unit for recording an image signal transmitted from the monitor camera device <b>1</b> or reproducing the image data from the recording medium; <b>26</b> denotes a superposing circuit for superposing the OSD display information generated by the OSD display circuit <b>27</b> on the image signal from the signal processing unit <b>24</b> by control of the malfunction report unit <b>222</b>; and <b>31</b> denotes a monitor for displaying an image from the monitor device <b>2</b> and OSD such as an alarm. Furthermore, the burst judgment unit <b>21</b> is formed by an NTSC/PAL detection circuit <b>211</b> and a burst presence/absence detection circuit <b>212</b> for detecting presence/absence of a burst signal.

Here, brief explanation will be given on the outline of the operation for reporting a malfunction to an administrator upon detection of the malfunction. The monitor camera device <b>1</b> transmits a color burst signal while switching it depending on the malfunction position and the burst detection unit <b>21</b> detects the content of the burst signal. When the burst signal frequency is switched from the normal 3.58 MHz to 4.43 MHz, this is detected by the NTSC/PAL detection circuit <b>211</b>. The burst signal OFF and the periodic ON/OFF of the burst signal are detected by the burst presence/absence detection circuit <b>212</b>. According to the detection result by the burst detection unit <b>21</b>, the malfunction position information judgment unit <b>221</b> specifies a malfunction position. When the frequency of the burst signal is 3.58 MHz, the monitor camera device <b>1</b> is in the normal state without any malfunction. When the frequency of the burst signal is 4.43 MHz, it is judged that the drive circuit <b>19</b> is in an abnormal state. When the burst signal is in the OFF state, it is judged that the lens iris unit <b>11</b> is in an abnormal state. When the burst signal ON/OFF is caused periodically, it is judged that the CCD sensor <b>12</b> is in an abnormal state. According to the judgment result information and the identifier of the monitor camera device recognized by the control unit <b>22</b>, the OSD display circuit <b>27</b> is controlled by the malfunction report unit <b>222</b> so as to display the identifier of the monitor camera where the failure has occurred and the failure position on the screen of the monitor <b>3</b> via the superposition circuit <b>26</b> for the administrator. Simultaneously with this display, the volume and the level of the buzzer <b>231</b> and ON/OFF repetition are changed for reporting the malfunction. The brightness, the color, the flashing period of the LED <b>232</b> are changed for reporting the malfunction. The audio guide for the malfunction occurrence and the malfunction position is performed by audio from the speaker <b>234</b>. Furthermore, the malfunction information, the malfunction position information, and the identifier of the camera which has failed are transmitted to a preset destination such as a PC and a mobile telephone by the Ethernet transmission circuit <b>235</b>. The administrator can know the malfunction via the PC or the mobile telephone at a remote place and ca rapidly take a countermeasure.

It should be noted that the embodiment has been explained with assumption that only one monitor camera device <b>1</b> is connected to the monitor device <b>2</b>. However, a plurality of monitor camera devices may also be connected and input to the burst detection unit and the signal processing unit <b>24</b> may be performed by using a switching circuit.

Next, explanation will be given on the flow of malfunction detection process and the malfunction report process in the monitor camera device <b>1</b> and the monitor device <b>2</b> with reference to <figref idref="DRAWINGS">FIG. 3</figref> and <figref idref="DRAWINGS">FIG. 4</figref>. <figref idref="DRAWINGS">FIG. 3</figref> is a flowchart of the malfunction detection process performed by the monitor camera device in the present invention. <figref idref="DRAWINGS">FIG. 4</figref> is a flowchart of the malfunction report process performed by the monitor device in the present invention.

The monitor camera device <b>1</b> in the imaging state monitors information on the signal level from the signal level detection unit <b>151</b> and judges whether the signal level is higher than a predetermined threshold value in step S<b>301</b>. If the signal level is equal to the signal for the exposure target, control is returned to step S<b>301</b> for monitoring the signal level. If the signal level is higher than predetermined threshold value in step S<b>301</b>, it is judged that “Wash Out” has occurred in the screen. Accordingly, it is judged in step S<b>302</b> whether the mode is the iris exposure mode or the shutter exposure mode. If the mode is the iris exposure mode, control is passed to step S<b>303</b> for judging whether the drive voltage of the lens iris unit <b>11</b> as an output from the iris circuit <b>19</b> is the target value. If the voltage is not the target value, control is passed to step S<b>305</b>, where it is judged that the iris drive circuit <b>19</b> is in an abnormal state. If it is judged in step S<b>303</b> that the drive voltage is the target value, it is judged that the lens iris unit <b>11</b> is in an abnormal state because the signal level is high in spite of that the iris control value is a control value for the closed state more than the threshold value (for example, the control value is not for the open state). When it is decided in step S<b>302</b> that the mode is the shutter exposure mode, it is judged that the CCD sensor <b>12</b> is in abnormal state because the signal level is high in spite of that in step S<b>304</b>, and the shutter speed control value is a value faster than a predetermined threshold value (for example, the control value is in the state of the maximum speed).

After this, in step S<b>308</b>, a counter starts counting to decide whether the abnormal state has continued for a predetermined time (such as 1 minute) and step S<b>309</b> decides whether the predetermined time (such as 1 minute) has elapsed. If the abnormal state has not continued for a predetermined time, control is passed to step S<b>310</b> where the counter is reset and then control is returned to step S<b>301</b> for monitoring the signal level.

If it is decided in step S<b>309</b> that the abnormal state has continue for a predetermined time, the malfunction position is specified in step S<b>311</b>. After this, according to the malfunction position specified in steps S<b>305</b>, S<b>306</b>, and S<b>307</b>, if it is judged that the iris drive circuit <b>19</b> is in an abnormal state, the frequency of the burst signal is switched from 3.58 MHz to 4.43 MHz; if the lens iris unit <b>11</b> is judged to be in an abnormal state, step S<b>313</b> turns OFF the burst signal; and if the CCD sensor <b>12</b> is judged to be in an abnormal state, step S<b>314</b> periodically turns ON/OFF the burst signal. That is, in this embodiment, the burst signal in the color signal is used as malfunction information, which is mixed with the luminance signal and transmitted as an image signal to the monitor device <b>2</b>.

Moreover, as has been explained with reference to <figref idref="DRAWINGS">FIG. 1</figref>, according to the failure information, simultaneously with the process of S<b>312</b>, S<b>313</b> and S<b>314</b>, the volume and the level of the buzzer <b>201</b> and ON/OFF repetition are changed and the brightness, the color, and the flashing period of the LED <b>202</b> are changed. An audio guide about the malfunction occurrence and the malfunction position is also performed by audio from the speaker <b>204</b>. Thus, the monitor camera device itself reports the malfunction and a person in the vicinity of the camera can also know the malfunction and rapidly take a countermeasure. Furthermore, information such as the malfunction information and the malfunction position information is transmitted to a preset destination such as a PC and a mobile telephone by the Ethernet transmission circuit <b>205</b>. The administrator can know the malfunction via the PC and the mobile telephone at a remote plate and can rapidly take a countermeasure.

In step S<b>401</b>, the monitor device <b>2</b> detects the content of the burst signal in the image signal transmitted from the monitor camera device <b>1</b>. When the burst signal frequency is 4.43 MHz, the monitor device <b>2</b> performs in step S<b>402</b>, on the screen of monitor <b>3</b>, OSD display that the iris drive circuit of the camera of identifier xx has failed as malfunction report process A. When the burst signal is OFF, the monitor device <b>2</b> performs in step S<b>403</b>, on the screen of monitor <b>3</b>, OSD display that the lens iris unit of the camera of identifier X has failed as malfunction report process B. When the burst signal periodically repeats ON/OFF, the monitor device <b>2</b> perform in step S<b>404</b>, on the screen of monitor <b>3</b>, OSD display that the CCD sensor of the camera of identifier xx has failed as malfunction report process C. According to the display on the screen of the monitor <b>3</b>, the administrator can know which monitor camera device is in an abnormal state and rapidly take a countermeasure for the monitor camera device in the abnormal state.

Explanation will be given on the image signal inputted to the signal processing DSP <b>15</b> with reference to <figref idref="DRAWINGS">FIGS. 5A and 5B</figref>. <figref idref="DRAWINGS">FIG. 5A</figref> shows a screen example and brief diagram of the image signal in the normal state. <figref idref="DRAWINGS">FIG. 5B</figref> shows an screen example and brief diagram of the image signal when a malfunction has occurred. In this case, the object is a person with the background having black left half and white right half.

The screen <b>501</b> in the normal state shown in <figref idref="DRAWINGS">FIG. 5A</figref> shows a person having a head <b>502</b> with the background which is black at the left half and white toward the right side of the screen. In this case, the image signal <b>503</b> includes a burst signal <b>504</b> for colour after the synchronization signal and the signal <b>502</b> corresponding to the head of the person is present in the middle of the obliquely increasing signal in the image portion. In this state, the exposure control by the microcomputer <b>17</b> is performed normally and the target signal level is obtained.

On the screen <b>505</b> in the abnormal state shown in <figref idref="DRAWINGS">FIG. 5B</figref>, “Wash Out” occurred and the person cannot be recognized. In this case, the image signal <b>506</b> has the burst signal <b>504</b> for color after the synchronization signal and the entire image portion <b>508</b> is a large level signal of white 100%.

Here, when the level of the image portion <b>508</b> is compared the preset threshold value, the level of the image portion <b>508</b> is higher and accordingly, it is judged that the monitor camera device <b>1</b> may be in an abnormal state and as has been explained with reference to <figref idref="DRAWINGS">FIG. 3</figref>, check operation is performed to decide whether the lens iris unit <b>11</b> or the CCD sensor <b>12</b> operates without any malfunction. Thus, not only by using the signal level of the image signal, but by checking whether the exposure iris control value and the shutter speed control value for the shutter speed are not abnormal values, it is possible to improve the malfunction detection accuracy. Moreover, even when the image signal is in an abnormal state, the burst signal is added to a position other than the image portion by the color encode portion <b>16</b> and accordingly, the signal information is not lost and can be detected by the monitor device <b>2</b>.

Screen display examples in steps S<b>402</b>, S<b>403</b>, and S<b>404</b> upon malfunction report will be explained with reference to <figref idref="DRAWINGS">FIG. 6A</figref>, <figref idref="DRAWINGS">FIG. 6B</figref>, and <figref idref="DRAWINGS">FIG. 6C</figref>. <figref idref="DRAWINGS">FIG. 6A</figref> shows a display example upon malfunction report A in the present invention. <figref idref="DRAWINGS">FIG. 6B</figref> shows a display example upon malfunction report B in the present invention. <b>6</b>C shows a display example upon malfunction report C in the present invention. It should be noted that explanation will be given here in the case when the identifier of the monitor camera device is “01”.

As shown in <figref idref="DRAWINGS">FIG. 6A</figref>, when the iris drive circuit <b>19</b> is in an abnormal state, the screen displays an OSD message “**Failure information report** “Drive circuit of Camera ID <b>01</b> has failed. Contact service center!!”” As shown in <figref idref="DRAWINGS">FIG. 6B</figref>, when the lens iris unit <b>11</b> is in an abnormal state, the screen displays an OSD message “**Failure information report** “Lens iris unit of Camera ID <b>01</b> has failed. Contact service center!!”” As shown in <figref idref="DRAWINGS">FIG. 6C</figref>, when the CCD sensor <b>112</b> is in an abnormal state, the screen displays an OSD message “**Failure information report** “CCD sensor <b>12</b> of Camera ID <b>01</b> has failed. Contact service center!!”” Thus, the malfunction position where the malfunction has occurred and the identifier (ID number) of the monitor camera is reported by the OSD message to the administrator. The administrator can know which monitor camera is in an abnormal state and rapidly take a countermeasure for the monitor camera in the abnormal state.

2. Embodiment 2

Explanation will be given on a monitor system according to a second embodiment of the present invention with reference to <figref idref="DRAWINGS">FIG. 7</figref> and <figref idref="DRAWINGS">FIG. 8</figref>. In the Embodiment 1, the monitor camera device detects a malfunction and a malfunction position and, the monitor device reports according to the malfunction position information the identifier of the monitor camera and the malfunction position to the display screen. In the Embodiment 2, the monitor camera device detects a malfunction occurrence and the monitor device reports that the monitor camera device has failed.

The malfunction detection process and the malfunction report process in the monitor camera <b>1</b> and the monitor device <b>2</b> will be explained with reference to <figref idref="DRAWINGS">FIG. 7</figref> and <figref idref="DRAWINGS">FIG. 8</figref>. <figref idref="DRAWINGS">FIG. 7</figref> is a flowchart of the malfunction detection process of the monitor camera device according to the second embodiment of the present invention. <figref idref="DRAWINGS">FIG. 8</figref> is a flowchart of the malfunction report process of the monitor device according to the second embodiment of the present invention.

The monitor camera device <b>1</b> in the imaging state monitors signal level information from the signal level detection unit <b>151</b> in step S<b>301</b> to judge whether the signal level is higher than a predetermined threshold value and performs S<b>309</b> and S<b>310</b>. The operations performed here are identical to steps S<b>301</b> to S<b>310</b> in <figref idref="DRAWINGS">FIG. 3</figref> and their explanations are omitted.

If it is decided in step S<b>309</b> that an abnormal state has continued for a predetermined time, the burst signal frequency is switched from 3.58 MHz to 4.43 MHz and the burst signal as malfunction information is mixed with the luminance signal, and the mixed signal is transmitted as an image signal to the monitor device <b>2</b> in step S<b>711</b>.

When the monitor device <b>2</b> detects that the frequency of the burst signal in the image signal transmitted from the monitor camera device <b>1</b> is 4.43 MHz in step S<b>801</b>, it displays an OSD message that the camera ID xx has failed on the screen of the monitor <b>3</b> as a malfunction report process in step S<b>802</b>. According to this screen, the administrator can know which camera device is in an abnormal sate and rapidly take a countermeasure for the monitor camera in the abnormal state.

3. Embodiment 3

Explanation will be given on a monitor camera device according to a third embodiment of the present invention with reference to <figref idref="DRAWINGS">FIG. 9</figref>. In the first embodiment, when judging the malfunction of the iris unit of the monitor camera device, a malfunction of the iris drive circuit <b>19</b> is specified by detecting the output of the iris drive circuit <b>19</b> (drive voltage of the lens iris <b>11</b>). In the third embodiment, a malfunction of the lens iris unit (iris open/close unit) is specified by using a hall element capable of detecting the open/close state of the iris open/close unit in the lens iris unit of the monitor camera device. Here, explanation will be given on the operation for specifying a malfunction position by detecting the malfunction of the iris unit which is different from the first embodiment and explanation on the other portions identical to the first embodiment is omitted.

When the lens iris unit <b>91</b> or the iris drive circuit <b>19</b> has failed, the iris open/close circuit <b>912</b> cannot be closed, the entire image has become bright, and the signal level of the image signal has become large. In this case, the exposure target calculation unit <b>171</b> sends a iris control value to close the iris open/close unit <b>912</b> to the iris drive circuit <b>19</b>. However, if the iris open/close unit <b>012</b> or the iris drive circuit <b>19</b> has failed, the iris open/close unit <b>912</b> cannot be closed and “Wash Out” occurs in the image. Here, because of the image of “Wash Out”, the signal level from the signal level detection unit <b>151</b> is higher than a predetermined threshold value and the iris control value is for closing. Since this state is judged to be out of the normal control range, the malfunction judgment unit <b>172</b> decides that a malfunction has occurred and the malfunction position detection unit <b>173</b> decided that the lens iris unit <b>91</b> or the iris drive circuit <b>19</b> has failed. Furthermore, the output from the hall element <b>913</b> which detects the open/close state of the iris open/close unit <b>912</b> has been detected via the amplifier circuit <b>92</b>. If the open/close value is not the target value with respect to the iris control value, it is possible to decide that the lens iris unit <b>91</b> has failed. If the lens iris unit <b>91</b> has not failed, it is possible to decide that the iris drive circuit <b>19</b> has failed. After a malfunction position is specified, the malfunction report unit <b>174</b> performs the malfunction position report operation in the same way as in the first embodiment.

According to the respective embodiments thus far explained, it is possible to detect the image of “Wash Out”, improve the detection accuracy, and improve the reliability of the camera device and the monitor system.

Especially, the camera device according to an embodiment of the present invention includes a iris unit for varying exposure, a shutter control unit for varying the shutter speed of imaging element, a signal processing unit for processing an image signal from the imaging element, and a control unit for controlling the signal processing unit and the entire device. The camera device further includes: an exposure target calculation unit for calculating a control value for controlling the iris unit or the shutter control unit so that the exposure will be a target value according to the signal level information from the signal processing unit; and a malfunction judgment unit for judging the malfunction of the device according to information on the control value obtained by the exposure target calculation unit and the signal level from the signal processing unit. Thus, when the iris is not in the open state and the signal level is high or when the shutter control value is at a high speed state and the signal level is high, the malfunction is judged, thereby detecting an image of “Wash Out” and improving the detection accuracy.

Furthermore, the control value obtained by the exposure target calculation unit is a iris control value for controlling the iris unit and/or the shutter speed control value for controlling the shutter control unit. When the signal level from the signal processing unit is higher than a predetermined level threshold value, the malfunction judgment unit compares the iris control value to a predetermined iris threshold value, thereby deciding the malfunction of the iris unit and compares the shutter speed control value to a predetermined shutter speed threshold value, thereby deciding the malfunction of the shutter control unit. Thus, when the signal level is high and the iris control value and the shutter speed control value are higher than predetermined threshold values, it can be judged that an abnormal state is present.

Furthermore, the iris unit consists of an iris mechanism unit and an iris drive circuit. The malfunction judgment unit detects information on the output value of the iris drive circuit and judges the malfunction of the iris drive circuit according to the iris control value and the output value of the iris drive circuit. Thereby, the malfunction of the iris drive circuit can be detected.

Furthermore, a report unit is provided for reporting malfunction information judged to be as a malfunction. When it is judged that a malfunction has occurred, the malfunction information is reported to the monitor device, from which the malfunction is reported to the administrator.

Furthermore, a unit or circuit judged to be in an abnormal state is specified and malfunction information corresponding to the unit or circuit in the abnormal state is reported by the report unit. This increases the convenience since the position where a malfunction has occurred is known and there is no need of searching the malfunction position upon maintenance.

Furthermore, the monitor system includes a monitor device for receiving a video signal and the malfunction information from the camera device. The monitor device includes a malfunction information detection unit for detecting the malfunction information, a malfunction position identification unit for specifying the malfunction position from the malfunction information, and a malfunction report unit for reporting the malfunction. When a malfunction is detected by the malfunction information detection unit, it is reported by the malfunction report unit. This enables the administrator to know the malfunction through an alarm display on the monitor connected to the monitor device or audio information such as a buzzer.

Furthermore, when it is judged that the camera device is in an abnormal state, the frequency of the color burst signal in the image signal is changed from a first frequency to a second frequency or the burst signal is switched ON/OFF, thereby the malfunction information is reported to the monitor device. In the monitor device, the malfunction information recognition unit detects that the first frequency is switched to the second frequency or the burst signal is present or absent and the malfunction report unit reports it outside. Thus, malfunction information can be transmitted while being superposed on the image signal. Accordingly, there is no need of increasing the connection for malfunction information which may increase the cost. Furthermore, the conventionally mounted NTSC/PAL detection circuit can be used as the malfunction information recognition unit and it is possible to suppress the increase of the cost of the monitor device.

The present invention has been thus far described according to the specific embodiments. However, the present invention may be modified and corrected in various ways without departing from the spirit of the invention within the range of claims.